Merkuro Calendar vs Rainlendar

Merkuro Calendar

• KDE Plasma users who want a calendar made for their desktop
• Linux users syncing Nextcloud, Google or Exchange calendars
• People who keep tasks and subtasks next to their events

Rainlendar

• People who want upcoming events and tasks always visible on the desktop
• Households or offices that mix Windows, Mac and Linux computers
• Users who like to restyle an app with skins and scripts
• Buyers who prefer a small one-time payment to a subscription

Merkuro Calendar

• Stable releases are for Linux. The Windows builds on KDE's site are nightly installers that KDE labels unstable and intended for testing.
• It depends on Akonadi and KDE PIM packages; without kdepim-runtime, the project says the calendar component is heavily restricted.
• The Kontact Flatpak that includes Merkuro lacks some desktop integration, such as the calendar applet plugin, so KDE recommends a distribution package.
• Proton Calendar cannot be connected, and services with non-standard calendars or task lists, such as Todoist, are not supported.

Rainlendar

• No mobile or web version. The site suggests syncing both Rainlendar Pro and a phone with Google Calendar instead.
• Sync with Google, Outlook.com, CalDAV and the other online services is limited to Pro, and Outlook support is Windows only.
• The Pro license is sold in euros, at 9.95 EUR; the purchase page shows no US dollar price.
• Rainlendar does not merge calendars from different sources; each stays a separate calendar shown in the same window.

Merkuro Calendar

Month, week and schedule views

The month view gives an overview of the whole month, the week view shows each day hour by hour, and the schedule view lists upcoming events in order.

Tasks and subtasks

A separate task view shows tasks and their subtasks as a tree, with filters that can be customized.

Local and online calendars

Supports CalDAV calendars such as Nextcloud, Google and Exchange calendars, iCal files and folders, and Kolab and Open-Xchange groupware servers.

Sync through Akonadi

KDE's Akonadi framework fetches, edits, creates and deletes events on remote services. The project recommends installing the kdepim-runtime package before starting the app.

Plasma clock widget integration

Events can appear in the calendar of Plasma's digital clock widget by enabling the PIM Events Plugin in the widget's settings and choosing which calendars to show.

Desktop and mobile layouts

The interface is designed for desktop, mobile and sizes in between, and the listing includes a mobile view. The project describes it as syncing across a Plasma desktop or phone.

Rainlendar

Events and tasks on the desktop

Events and tasks are kept in separate lists that sit on the desktop, and both can also be shown in the calendar window. Several windows can be shown at once, such as the current and the upcoming month.

Alarms with snooze

An alarm can fire ahead of an event or task and be snoozed for later. A single event or task can carry more than one alarm.

Skins and Lua scripting

Skins change how the windows look and can be mixed together, categories change how individual events appear, and Lua scripts can alter how a skin behaves or fetch content from the internet.

Standard iCalendar storage

Events and tasks are saved in the iCalendar format (RFC 2445), by default in a local .ics file, and can be exported or imported as .ics. Settings and events are backed up automatically every day.

Sync with online calendars (Pro)

Pro connects to Google Calendar and Tasks, Office 365 / Outlook.com, CalDAV servers, network shared calendars, Remember The Milk and Toodledo, and to Microsoft Outlook on Windows.

Quick Add and printing

A Quick Add widget creates an event or task from one line of text, including a recurrence pattern and a category. Events and tasks can be printed as a list or a calendar layout, or written to a PDF.

Merkuro Calendar

• Merkuro Calendar$0

  The complete app, installed through Discover, a distribution's package manager or the Kontact Flatpak. Release 26.08.2 is dated 2026-10-08.

Rainlendar

• Rainlendar Lite€0

  Events, tasks, alarms, skins, printing and iCalendar import and export, with data kept in local files.

• Rainlendar Pro€9.95

  one-time purchase, lifetime license per user

  Adds sync with Google Calendar and Tasks, Office 365 / Outlook.com, CalDAV, Remember The Milk, Toodledo and Outlook on Windows, plus CSV import and export.

Merkuro Calendar

No public discounts listed.

Rainlendar

• Lifetime license

  Lifetime Pro license with free upgrades

  The purchase page describes Pro as a single purchase of a lifetime license. The homepage says existing license holders upgrade for free, and the FAQ says one license covers one user on several computers.